Phonograph



Patented Feb. 1, 1938 V 4 I i Q UNITED STATES PATENT- OFFICE PHONOGBAPH Hudson It. Searing. New York, and Axel F. Shipstedt, North Pelham. N. Y... assignors to Radio Corporation oi America, a corporation of Delaware Application January 2'1, 1932, Serial No. 589,082

a i 4 01a (61. 274-4) For many years phonograph records have been the driving shaft or spindle l3 of the machine and restricted to a limited length by the size of the which has diametrically opposite slots l4 and I5 disc or cylinder on which the impression has in its lower end adapted to be dropped over a been made. For clearness, the inscription has pin l6 which extends at one side only from the 5 been made on a certain scale and the machine lower part of the driving shaft I3. The'slot l4 5 has been geared to operate at the speed' necessary (Fig. 2) is comparatively short so that the upper for clear reproduction. A slight adjustment of end of it rests on the pin and holds the mechathe speed mechanism has been provided in order nism above the wooden plate or motorboard ll to insure its running at the standard speed. This, which usually covers the metal casing l8 in which 10 in the disc type of machines, for example, has the driving member and other related parts are.l0

been '78 revolutions per minute. Modern imcarried. The slot M (Fig'. 3) is of greater length provements have made it possible to record the so that when it is dropped over the pin I6 the sotmds on a considerably smaller scale, providing speed control mechanism rests on the base or an increase in the length of the composition on motorboard l'l.

v a single record. These new records are driven The speed mechanism is shown in section in 15 at a much lower standard speed;' In the disc Fig. 5. The hollow shaft I2 is the central memmachines, above referred to, the standard speed ber of a differential gearing. Ordinary gears and has been reduced from '78 to 33 revolutions per pinions may be used. Preferably, however,-the minute. The playing time of the new single re'cgearing is in the form of an annular ball bearing, ords is about three times as long as one of the the ballslfl serving as the intermediary pinions 20 ld r cords, engaged frictionally between a collar 20 on the The old machines, however, were not adapted central shaft, equivalent to a central gear, and to such a substantial change of speed. Their an outer ring 2!, equivalent to an outer gear with speed adjusting mechanism was adapted only to internal teeth. The turn table II is mounted on' correct slight departures from the standard. a hub 22 which is supported and free to rotate 5 New machines have been made operating at the t e pp end f th central Shaft p d proper speed for the new records. Our inven-- 12. The annular series of balls are carried in a tion provides a mechanism of a very simple charretainer or ball cage which may be of any usual acter by which a machine of the old type can be or suitable design. Fi 6 sh ws the same demade to operate the turn table or other record veloped 011 Straight line- There are two re- 30 carrier at either of two speeds suitable respectainer rings 28 and 24 respectively which are tively for the old and for the new records. Our shaped 110' engage the balls n hold them In improved mechanism may be incorporated in an place but with freedom of rotation. Between old or new machine as a regular part of it or each pair of balls isa rivet 25 passing through the may be in the form of an attachment adapted to two retainer rings and the hub 22 of the turn 35 replace the regular turn table, or other record table, with filler blocks 26 to preserve the correct carrier. The accompanying drawings illustrate spacing. The details of this ball retainer and embodiments of the invention. connections may be varied greatly. The turn Fig. l is an underside-perspective of a turn table table is thus fastened to the series of balls so that with the speed control mechanism; it moves with them about the central vertical axis. 40

Fig. 2 is a side elevation of the same mounted The shaft and the outer ring carry annular bearon the driving shaft of the machine; ing rings 20"- and 2| specially shaped to engage Fig. 3 is a similar view in a second position; the balls, as in ordinary ball bearings.

Fig. 4 is a view similar to Fig. 3' showing an The central hollow shaft I2 is driven'at the 5 alternative construction; 1 same speed as the main shaft of the machine (78 Fig. 5 is a central vertical section through the revolutions per minute for example "in the old speed control device; machines); If the ring 2 Us held stationary, and Fig. 6 is-a detail of the same in elevation; assuming that the balls act as true pinions or Fig. 7 is a similar view of an alternative conengaging gears, the series of balls will rotate aboutstruction. the central axis at a speed which is a function of 50 .Referring to the drawings, the turn table II the radii of the lines of contact which the balls is the usual metal disc covered with felt on which make with respective inner and outer retaining the records are placed. It carries on its under rings, 20* and 2|, or the radii of the pitch lines side a speed control mechanism, the central memof central and outergears respectively where her of which is a hollow shaft l2 which fits over common pinions are used. The rotational speed 55 70 provided with a pin 2| which enters of the balls or pinions about the central shaft or spindleisequaltotheratio ofthelesserradiito the sum of the two radii times the rotational speed of the central shaft. This type of mecha- 5 mm is, therefore, specially adapted to secure in compact and simple construction, a substantial reduction in speed. for example, from 78 to 33 revolutions per minute as in the present case.

flheuseofballainreversaloftheirusualantifriction function. is p cally efl'ective because with a good fit their f ction against the adjacent rings is in excess of the friction or resistance which the needle oflers to the turning of the table.

- In practice it appears that this resistance from the needle is neligible. The required slow and uniform speed is maintained without any more variation than can be taken care of by the usual readjusting mechanismin the machine.

Various schemes may be provided for holding so theouterringstationsrysoastosecurethereduction of speed. 2 and 3 illustrate one arrangement. The driving shaftll is provided with a projecting pin I! at one side only. The central hollow shaft if has the two'slots of dif- 25 ferent lengths. When the'longer slot is placed over the pin as in Fig. 3, the ring 2| rats on the fixed wooden base or motorboard II. The friction between these parts is generally suilicient to hold the ring against movement while the hollow 80 shaft and the balls rotate about the vertical axis, the rotation of the balls carrying the turn table against the slight resistance of the needle. However, when the shorter slot is dropped onto the pin it as in Fig. 2, the ring 2| is held clear of the 86 base or 'motorboard l1 and is free to rotate. In such case, the entire mechanism rotates at the same speed as the driving shaft and the turn table also rotates at the same speed.

, It will be apparent that in this arrangement the Q base or motorboard il serves as abrake or stop which isbrought 'into engagement with the ring f ii to hold the latter stationary and cause the driving of the turn table at the diiferential speed; or which is released fromthe ring 2i so as to a cause the driving of the turn table at the same,

speed as the main shaft. Various otherschemes maybeusedfor'brakingorlockingtheringin' one position and releasing it inthe other.

so turntable H isusodandisdrivenateither of the two duired speeds. The invention may, howturn table 21, (l'lg. 4) which carries a dflercntial searingidentioalwiththatshownintheother figures; the ring Ii, however, beingjprovided slots it in its periphery. The hub has a as of slots 8. at diametrically opposite points areadaptedtobeloweredintothepln "of main driving shaft. 'In this position the ring may be in contact with or slightly above wooden base or motor-board l'l, the lat of slots 28 and thus positively prevents rotation the ring and produces rotation of the turn tab] at thedesireddifferential speed. H

Also with the arrangement of Figs. 2 and'3, 7 ring ll maybe roughened on the bottom, asy application of a felt strip or otherwise, so as to secure a stronger grip on-the base or motorboard IT, or may be provided with a variety of other devices which hold it fast on the motorboard in the lower position and release it in the upper 5 position. Similar with the attachment described in Fig. 4, various other gripping or locking means may be provided to hold the ring 2i fixed on the base or motorboard l1. w

Instead of the ball bearings illustrated in Fig. 6 10 we may use an arrangement of Fig. 7 which is similar to a roller bearing, the rollers being carried by retaining rings 32 and 33 and the bearing faces of the centralhollow shaft and the outer ring being similarly modified. The pins of the 15 rollers 34 will be extended through the retaining rings I! and 33 and fastened to the hub 22 which carries the turn table II. The pins are illustrated at 35. The balls, rollers, pinions, or thelike, (which are referred to herein generically as" 20 pinions) above described may be applied equally to the use of a single turn table with means for braking or releasing the outer ring or to a separate attachment which replaces the regular turn table and which upon insertion secures the outer ring in fixed position.

Various other modifications may be made without departing from the invention as defined in the, following claims. a

What we claim is: I 80 l. A change-speed mechanism for a phonograph comprising in combination a turn table, a central shaft, a ring surrounding said shaft, pin ions connected to said turn tableand located between said ring and said shaft and forming thereas with a unitary differential gearing, said shaft being hollow and being adapted to engage the driving shaft of the phonograph in either of two positions, in one of which said ring engages and is held by a fixed part of the phonograph, and in u the other of which it is free.

i 2. In a phonograph turn-table construction, the combination of a hub adapted to be placed upon and have non-rotative engagement with a-spindle of a phonograph; a support revolubly mounted on 5 said hub, a turn-table carried by said support and means arranged in said support for operative association of said spindle receiving member with said turn-table whereby the latter is operated by said phonograph spindle at diiferential speed with 5 said hub being provided with a bore for receiving a spindle of a phonograph drive mechanism whereby said tum-table is supported on said spinand is revoluble independently thereof, and operative connections between said hub and said so turn-table whereby the latter is actuated by said spindle ata diiferent speed with respect thereto. 4.Insdeviceoithe'classdescribed,thscombinationof a hub member adapted to be supportedon'and have operative engagement withja g .mindleo r osraphdnving.a

support revolubly by said hub, a turntable fixed to said support concentrically with said hub member, and reduction gearing inter-' posedbetweensaidhub'memberandsaidsupport for actuating the latter and said turn-table by said spindleat reduced speed with respect thereto and inthe same direction'as said spindle.

. HUDSON R. BIARING. 

